The subject matter described herein relates to methods and systems for operating a wind turbine and a wind turbine arrangement, and more particularly, to methods and systems for determining at least one position of at least one movable portion of the wind turbine.
At least some known wind turbines include a tower and a nacelle mounted on the tower. A rotor is rotatably mounted to the nacelle and is coupled to a generator by a shaft. A plurality of blades extend from the rotor. The blades are oriented such that wind passing over the blades turns the rotor and rotates the shaft, thereby driving the generator to generate electricity.
Operational parameters like rotor speed, rotor position, blade bending or deflection and tower bending or deflection are used to control a wind turbine. Usually, all of these parameters are provided by customized sensors. Examples of sensors include: strain gauges, incremental encoders, absolute encoders, and acceleration sensors, and are used to measure the rotor speed, rotor position, blade bending or deflection, tower bending or deflection, tower acceleration, main shaft bending and blade angle. Some of these sensors are sensitive, cost intensive or unreliable.
Many different sensors are used to provide certain operational parameters for the wind turbine control system, for example rotational speed, tower bending, shaft bending, and blade pitch. This increases the costs of each single sensor, and for different sensors different failure detection algorithms or devices may be used. Extensive engineering effort is required to specify, design and implement these sensors. It is desirable to provide a more reliable and cheaper method or arrangement to determine the operational parameters of the wind turbine.